Lumia 950 huge screen calibration problem. Please test and post results.

cristixxxlog

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So, there was another thread about this problem, but I made this one with a poll, so we will know better how many people have this problem.

The problem:
In dark scenes videos and images (notably wallpapers and video samples, not exactly photos/videos made with the phone) exhibit awful banding, blocking and ringing artifacts. Black/dark-brown spots/stains of wrong color where it should be a normal gradient.
It seems to be a problem of screen calibration, mainly too high gamma level. I managed to replicate this on the computer boosting gamma level higher.

How to test:
- download on both phone and computer the gammatest-xda.png image attached.
- go into a pitch-black environment and boost the phone's brightness to 100%. This is needed to better see the problems. The dark environment is essential. As more light is in the room, the problem starts to be less noticeable, and in normal daylight outside is basically unnoticeable. This has nothing to to with addaptive brightness and the problem does not go away, simply the human eye adapts to more light so does not "see" the problem anymore. - THIS IS IMPORTANT!!!


Now observe how it is rendered on the computer (considering we have a correct calibrated monitor) and how it is rendered on the phone.

The image:
- each block has a background color of different shades of gray, starting with block 21 (RGB 21-21-21) untill block 0 (RGB 0-0-0) wich is clear black.
So 9 is RGB 9-9-9, 13 is RGB 13-13-13 and so on....
- the numbers are all pitch black (RGB 0-0-0)

What is suppose to look like:
- nice looking and gradual gradient. The switch from one box to the next must be discrete and barely noticeable.
- starting around box 6 to 0, the majority of people should not be able to distinguish the numbers anymore because the background is more and more black.

What looks like on my 950:
- all boxes except 2 to 0 are far too bright. The 21 to 11 boxes seems ok, you can see that color gets gradually darker.
- from 10 to 5 looks like the same shade, not different from box to box and TOO BRIGHT compared to the reality. It should be much darker.
- box 4 is darker, but still way too bright.
- box 3 is HUGELY different. It looks like a dark brown. While closer to reality is still too bright, but compare it to 4, it is a MASSIVE difference. 4 to 10 are WAY TOO BRIGHT.
- box 2 is hugely different from 3 and like night and day compared to 4-10. Looks to me that 2 to 0 are perfect rendered. but the 4 to 10 are way off, huge difference that ruins dark scenes in videos.
- I can clearly see all the numbers from 21 to 4, even if I'm drunk as hell. 3 is harder to see but I have no problems seeing it. 2 to 0 I cannot see any of the numbers.

Attached I've put a photo of the 950 (to the left) next to my wife's Sony Xperia Z3 Compact (to the right). The photo is overexposed because of the dark environment, but that it is not the point. The point is you can clearly see the differencies between the shades on the 950. On the Z3, although has poor black levels, it has a normal gradual shift of the shades from box to box. In real life basically looks perfect, like on the computer.

So, if you want to post images of the display here please post PHOTOS OF THE SCREEN made with another phone/digital camera and NOT A SCREENSHOT, as the screenshot is totally useless (screenshot captures the data from the screen and not how the screen is rendered, so different screens, different looks).

I'll post this later also on the XL forum, as I suspect they do not have this problem.
I've checked both 950 and 950 XL (from the store) inside the same vodafone store together with my 950 (that is bought from orange) and in the exact same conditions and both 950's suffer from this problem but NOT the XL. The XL rendered perfectly.

Please take some time to test this and post your conclusions (and vote). Also, try and respect the dark environment, because it is the most important. It is important for everybody and if we really have a problem with the screens (HW) we should let MSFT know and go and replace out handsets.
 

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cristixxxlog

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It is important to test it with the image provided. There are scenarios, of course, that this problem doesn't come up, but on videos at least, it greatly depends on the source also, the gradients in pictures, the bitrate etc. And some videos simply do not have that complex dark scenes.
This image is all there is needed to see if there is a problem. Many may say they do not have a problem simply because some do not watch a movie in bed, at night, with the lights very low or totally off for example. Or do not use wallpapers with grey gradients...

For example, to see how is affecting videos, check this video in Edge. Or myTube, doesn;t really matter. I tested including with HI-Res samples downloaded in HDm full-HD, 2K etc Also, do it in a dark room, or better a completely dark one to see the mess in all it's glory.
https://www.youtube.com/watch?v=sGbxmsDFVnE - Take special attention on scenes transition. When the screen starts to get darker, you can clearly see the problem. Also, the scene with the crushed Vader mask. The background is all messed up. Also the closeup of Kylo Ren, you can see a big black stain on the left shoulder (his right shoulder) and the part of his mask that covers the mouth has a very bright shade of grey. That is not normal.

I must repeat myself: The best test that excludes the source thingy, compression, bitrate and whatnot, is this gamma test image. If it looks like mine and totally different from what you see on the computer, then you have a problem with screen calibration. The darker the environment, the uglier dark scenes in videos will look.
The gamma curve is way off. Possibly also some contrast is off, but for sure gamma has a problem in this device. You can test the same video on your computer, boosting the gama level higher. Then you'll see the same mess in that clip also in your computer.
 

TheChazas

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In some cases, even on 25% brightness + Battery saver which reduces brightness too, I can see weird blacks, like low bit-rate image, on Pictures, Movies, Gifs and etc.

And to add, seen people talking about this back in December, on both 950 and 950XL.
 
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cristixxxlog

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thank you. please also vote in the poll.

Can a moderator make this topic sticky? It could be a major problem related to drivers (something simmilar happened to Surface users, and the culprit was a bad gpu driver) or screens themselfes.
Must have as many users test and vote as we can in order to understand the problem and make Microsoft aware.

Sent from mTalk
 
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0 to 3 totally black.
4 to 10 seem to be the same gradient.
11 to 21 there is some gradient in big steps.

I tried with different settings in the color profile, and makes some differences in the result.

There is a problem but not too big for me.
 

cristixxxlog

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@Michael, I assume 3 to 4 is a totally different color and 4-10 look way brighter than normal.... You shouldn't see any number lower than 7 or 6...

Sent from mTalk
 

RuleOfSines

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Here you go, camera didn't quite capture it but block 3 is actually RED on my screen.
 

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cristixxxlog

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@RuleOfSines 640 has a normal gradient. That is how it suppose to look like (except the exposure, of course).

Doesn't matter the FW, nor the SO, nor any combination between them.
Both old and new FW has this problem.
 

TheChazas

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Checked on L950 .63 and newest firmware. been the same since stock.

By the way, tittle and pool question/answers, do not match with the problem in my eyes, People don't understand what they are asked and what is about.

@cristixxxlog, did you reported this anywhere else? cause here we won't get any attention from MS.
 

cristixxxlog

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@TheChazas - not yet, but I'll raise the problem inside MSFT forums today and maybe an email to somewhere like support.


Maybe I can convince WC to test their samples and write an article about it?





The title and questions can be modified, but that was what crossed my mind when I made it...



PS: Another vodafone store, another 950 with messed up screen. Didn't see a XL to test. The Irony: L550 didn't had this problem....
 

TheChazas

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Thanks for your effort. What about Windows Feedback? on Phone or MS web?

WC could really make a report about this, would raise more attention.

I think it is for all L950 devices not for just some, it is just overall problem, lets hope it is only software, driver or firmware that will get fixed, but not a hardware, screen problem. Heard that it is the same for 950XL, in early December, I have read about it, with some pictures.
 

RuleOfSines

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I have noticed on my 950, i get occaisonal display crashes or something of that nature when unlocking the phone. The display falls to a 16 color pallete or something similar before recovering.
 

cristixxxlog

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Well I too suspect it is software, probably bad driver. Nobody denied the problem yet and 2 out of 2 samples in store have the same problem.
I'll try today to put this topic also on the XL forum and raise the problem on MSFT forums, where some folks from there can answer.

In the feedback app it is almost impossible to explain the problem since I cannot upload images.

I'll try and escalate the problem on as much places I can.
 

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